Utilization of fresh human tympanic membranes for structural analysis and cytokeratin immunocytochemistry implementing resin techniques.

CONCLUSIONS: The results of this study have demonstrated for the first time that tympanic membrane (TM) structure is preserved following removal of fresh, normal tissue from patients undergoing surgery. Greater clarity has been demonstrated using resin sections than in previous studies on paraffin sections. Of particular note, cytokeratin (CK) immunocytochemistry was successfully performed on resin sections, which has not been previously reported. This may have potential applications for future work involving tissues that express CKs. OBJECTIVES: To analyse the structure of normal, fresh human TM specimens after surgical removal and to evaluate their CK immunocytochemistry using resin techniques, neither of which have been demonstrated previously. MATERIAL AND METHODS: Seven TM specimens were removed during surgery and then preserved in a modified Karnovsky's fixative. Semi-thin and thin sections were examined by means of light and electron microscopy, respectively. For comparison purposes, paraffin block-embedded specimens were also sectioned. CK immunocytochemistry was performed on semi-thin sections using standard immunoperoxidase techniques, with expression being demonstrated using light microscopy. RESULTS: The three-layer architecture of the TM was preserved. The morphology of the TM was vastly superior in the semi-thin resin sections than in the thicker paraffin sections. The outer, middle and inner layers were clearly demonstrated. The integrity of the outer epithelial layer was maintained, with an outer keratinizing stratum corneum and underlying stratum granulosum, stratum spinosum and stratum basale layers resting on the basal lamina. The thin inner mucosal layer was also viable, consisting of simple squamous or cuboidal cells. Preservation of the middle lamina propria was achieved, with demonstration of the outer radial and inner circular fibres. CK immunocytochemistry utilizing resin techniques provided excellent staining of CK 7 and 8 in the inner layer, with positive staining of CK 5 and 10 in the outer layer.

Sterile abscess mimicking recurrent tumour in the cerebellopontine angle.

Vestibular schwannomas are the most common tumours encountered in the cerebellopontine angle (CPA) region, accounting for 90 per cent of all lesions. Early pyogenic abscess following surgery and delayed abscesses due to retained foreign bodies have been reported. We describe a case of sterile abscess of unknown aetiology in the CPA region, occurring 13 years after surgical excision of a vestibular schwannoma. The clinical and radiological features were suggestive of recurrent vestibular schwannoma or malignant transformation. We believe this is the first reported case of delayed occurrence of sterile abscess in the CPA region. Further the diagnostic difficulties of such rare lesions occurring in the CPA after vestibular schwannoma surgery are discussed.